A206727 - OEIS

A206727

Number of nX1 0..2 arrays avoiding the pattern z-1 z-1 z in any row, column or nw-to-se diagonal

3, 9, 25, 69, 190, 523, 1440, 3965, 10918, 30064, 82785, 227959, 627714, 1728490, 4759616, 13106205, 36089594, 99377264, 273647872, 753524044, 2074923809, 5713565277, 15733025007, 43322875275, 119295019315, 328493931740

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OFFSET

1,1

COMMENTS

Column 1 of A206734

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 3*a(n-1) -2*a(n-3) +a(n-5).

Empirical: G.f.: -x*(3-2*x^2+x^4) / ( -1+3*x-2*x^3+x^5 ). - R. J. Mathar, Jul 17 2014

EXAMPLE

All solutions for n=4

..0....0....1....0....0....1....1....1....0....0....1....1....2....2....0....1

..1....2....2....2....1....0....2....2....0....1....2....2....1....2....1....1

..2....0....2....2....2....1....1....2....2....1....1....2....0....0....0....1

..0....0....1....0....1....1....1....0....0....0....2....2....2....0....1....0

CROSSREFS

Sequence in context: A005322 A103780 A211288 * A211296 A098182 A211300

Adjacent sequences: A206724 A206725 A206726 * A206728 A206729 A206730

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 11 2012

STATUS

approved